CA1186445A - Hydrocurable ambient curing polyepoxide coating and adhesive compositions and method of using them - Google Patents

Abstract

Abstract of the Disclosure Resin-forming polyepoxides are mixed with poly-oxazolidinyl compounds or polymers containing pendant oxazolidinyl groups in which the carbon atom in the 2-position of the heterocyclic ring is substituted with saturated hydrocarbon groups, such as dialkyl, or with an alkylene group forming a saturated ring with the carbon atom in the 2-position of the oxazolidinyl ring to form, in the absence of water, a stable composition which can be stored in closed containers for months without undergoing gelation. When such compositions are spread into films and the films exposed to moisture at ambient temperature, e.g., to ambient air having a relative humidity of at least 20% and temperature of about 15° to 25°C., the polymer serves to react with and cure the polyepoxide.

Description

~18~

HYDROCURABLE AMBIENT CURING POLYEPOXIDE COATING
AND ADHESIVE COMPOSITIONS AND METHOD OF USING THEM
BACKGROUND OF THE INVENTION
This lnventlon relates to coating, impregnatlng3 and adhesive compositlon3 of a resin-forming polyepoxide mixed with a poly~unctional compound containlng c~cllc oxazolidinyl groups.
Polyepoxides3 such as, ror exampleJ those obtained by reacting epichlorohydrln with polyhydrlc phenols in the presence o~ caustic~ are promlslng materials ~or use ln many lndustrial appllcatlons as they can be reacted with curlng hgents to form ln~oluble in~uslble products having good chemical reslstance. The conventlonal polyepoxide-curing agent systems, however, have a drawback that greatly limit~ the industrial use o~ the polyepoxides.
The known mixtures comprising the polyepoxide and curing agent set up rakher rapldly9 and thls i8 true even though the mlxtures are stQred in air-tlght containers away from moisture and alr and even though the temperature i~
malntained quite low. Thls dlfficulty necessltates a mixing o~ the co~ponents ~ust be~re use and a rapid use of the materlal before cure sets in. Such a procedure places a considerable burden on the indlvldual operators~
and in many cases, glves inferlor products resulting from ine~ficient mlxing and too rapid operations.

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Numerous at~empts have been made to provlde a latent curing agent for polyepoxides~ by whlch is meant the type of resin formlng organlc compound containing a plurality of vic-epoxy groups of the formula C--C
Such compounds may be saturated or un~aturated, aliphatic, cycloaliphatic, aromatic, or heterocycllc and may be substituted, lf desired, with substltuents such as chlorine atoms~ hydroxyl groups, ether radlcals~ and the like.
Holm, U.S. patent 3S291,775 and Gardner and Keough, U.S. Patent 3,547,880 di~close the use of certaln polylmlnes obtalnable by reactlng a ketone or aldehyde with a polyamlne to cure or reslnify a polyepoxlde.
Hankins and Emmons, U.S~ patent 39037,006, disclose that copolymers of 5 to 25% by weight Or an N-(acryloxyalkyl)-oxazolldlne or an N-(acryloxyalkyl)-tetrahydro-1~3-oxazlne embraced by the ~ormula C=C ~C~2~n~ C~2~m COO l CH 2 ~ m ?d~

where n i~ an lnteger havlng a value of 1 to 2, m i8 an integer havlng a value of 2 to 3, Rl, when not directly Jolned to R2, i~ selected ~rom the group consistlng of hydrogen, phenyl~
benzyll and Cl-C12 alkyl groups 9 R2~ when not directly Joined to R~ selected rrom the group consisting Or hydrogen and Cl-C4 alkyl groups and .
Rl and R2, when directly Jolned together3 form a 5- to 6-carbon ring wlth the attached carbon atom of the ring ln the ~ormula, i~eO, Rl and

3 ~ 6~

R , wnen Jolned together, are celected rrom the group conslsting o~ pentamethylene and tetramethylene, can be mixed with polyepoxides ~or the production of inso1uble and lnfuslble crosslinked coatlng~. There i8 no suggestlon ln this patent that the copolymers in which and R are independent saturated hydrocarbon groups or together an alkylene group forming a 5- to 6-carbon ring w~th the attached carbon of the rlng in the formula would provide distfnctive and unexpected storage-stabillty properties that are lacking ln those copolymers in which elthe~ or both Rl and R2 ls, or are, hydrogen atoms.
and ~ are attached to the 2-positlon carbon in the heterocyclic ring of the formulaD
DESCRIPTION OF THE INV~NTlON
.
It i~ an ob~ect of the lnvention to provide a new class of latent curlng agents ~or polyepoxides. It is a further ob~ect to provide new curing agents for polyepoxides that are substantlally unreactive wlth polyepoxldes when stored under atmospheres substantially free of moisture. It is a ~urther obJect to provide new curing agents that can be premixed with the polyepoxlde~
and the mixture stored or shipped without danger o~
premature gelation. It i~ a further obJect to provide new compositions containing polyepoxides that undergo cure only wherl in contact with moi~ture. It i9 a further obJect to provide a new process for curlng polyepoxides that ls partlcularly useful ~or the preparation of surface coating~. It ls a ~urther ob~ect to provide new curing agents for polyepoxides that may be cured to prepare high sollds or solvent-free coatings~ These and other obJects of the inventlon wlll be apparent ~rom the following detalled descrlption thereo~.
In accordance with the present invention7 it has been dlscovered that "one-pot" coatlng compositlons based on h polyepoxide can be prepared with a ~1 .1 ~ h polyfunctlonal ~ompound or polymer containing a plurallty of pendant 2,2-dialkyl-oxazolidlnyl or 2,2~alkylene-oxa7olldlnyl groups of the ~ormula ~C~2~m -N~ ~0 where m ls an integer having a value o~ 2, Rl and R2 are lndlvidual alkyl groups, e.g.
having 1 to 12 carbon atom~ or together may be a pentamethylene or tetramethylene group forming a 5- to 6-carbon rlng wlth the attached carbon of the ring in the ~ormula, or the analogous 2,2-dlalkyl- or 2,2 alkylene-tetrahydro-l,3-oxazlnyl groups o~ the formula IA where m is 3. These groups are generically referred to hereinafter as cycllc oxazolidinyl groups~
It has been discovered that the polyepoxide may be mlxed with a ?olyrunctlonal compound or a vlnyl addition or condensation poly~er contalnlng a plurality of pendant (and/or termlnal~ cycllc oxazolldinyl groups o~ Formula lA
in the absence o~ water and rormulated wlth conventional non-aqueous ingredients, such as pigments, flllers~
dispersing a~ents3 and rheological agents to prepare coatlng composltions that can.be packaged in closed contalners in the absen~e Or moi~ture and stored therein ~or extensive period of time without reaction between the polyepoxlde and the compound or polymers contalnlng the pendant oxazolidlnyl groups o~ the Formula IAo However, when the composition ls subsequently spread out and exposed to rr~oist atmosphere~ the composltion sets up or cures even at amblent temperature (of about 15 to 25C) to form a hard, lnfuslble film.

The poly(formula IA cycllc) compound may be o~tained ln any of several ways. An N-hydroxyalkyl-2,2 dialkyl- or 2,2-alkylene compound having a cyclic group o~ Formula IA
may ~lrst be prepared by reactlng dlethanolamlne or dlpropanolamine wlth a dialkyl~etone~ or a cyclopentanone or cyclohexanone. The resultlng cyclic ox~zolldlnyl compound can then be converted into a poly(ester) by uslng lt $o transesterify a polyester of a polycarboxylic acld, ~uch as dlmethyladipate, dimethylsuccinate, and 80 on.
The resultlng poly(IA) cycllc compound ~s efrectlve as a curing agent for a polyepoxide when mlxed therewlth and then applled, ln the mlxture, ~or coating, impregnatlng, or binding in the presence of moistureO It is essentlal that there be no other amine nltrogen groups in the polyfunctlonal compound containlng the cyclic IA group~.
Simllarly the N-hydroxyalkyl cyclic oxazolidlnyl compound may be reacted with a polyisocyanate, such as a diisocyanate or trilsocyanate. Then~ the resultlng product may be mixed wlth the polyepoxlde in the absence of molsture, ln which conditlon lt remains e~rectlvely stable for months but upon spreading out the composition ln the ~orm of a fllm and exposlng the latter to water or atmo~pheric moisture, the compositlon is cured or cros~llnked to an in~usible and lnsoluble conditlon, The vlnyl addition polymers containing the pendant group~ of formula IA are preferably copolymer~ of the 2,2-dialk~yl~ or 2,2-alkylene-rnonomer3 o~ ~ormula I above with at least one other monoethylenically unsaturated copolymerizable monomer of non-lonlc nature having a group o~ the formula H2C=C<, such as styrene3 vinyl toluene, acrylonitrlle, and Cl to Clg alkyl esters of acryllc acid or ~ethacrylic acid3 e.g., methyl, ethyl, butyl~
cyclohexyl, and 2-ethylhexyl (meth~acrylate. The copolymer may contaln a~ little as 5% by weight of the ~f,~
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monomer of ~ormula I up to aB much a~ 70% by wei~ht thereof, but preferably from about 20% to about 35% by welght thereof. It is essentlal, however, that aIl of~~the monomer o~ Formula I present ln the copolymer consist Or the 2;2-dialkyl or 2,2-alkylene substltuted groups de~ined by formula IA above. Of these monomers, the preferred ones are the 29 2-dialkyl-oxazolldinylethyl (meth)acrylate.
The copolymers may be prepared by solution (organic solvent~ polymerization as hereinafter described in Example IA).
The polyepoxides and poly(runctional) compounds or vlnyl additlon copolymers havlng pendant formula IA groups may be mlxed ln a wide range of proportions. In general, however~ the amount of poly(functional) compound or copolymer used should provide approximately one equlvalent of amine (developed ln contact ~lth water or molsture ln the ambient air) ror each equivalent oP epoxy groupO
Depending on the partlcuiar co~positlon or u~e, the ratlo of amine/epoxy equivalency may vary ~rom about 4:1 to about 1:4 or poæsibly even over a wlder range ln some lnstances. As used herelng the equlvalent amount of poly(functional) compound or copolymer is that amount needed to furnlsh one amino hydrogen upon hydrolytic opening of the rormula IA rlng to produce a group of the ~ormula -N(H)-(CH2)m-OH (herein designated ~ormula IB) wlth llberaklon of a ketone RlR2C=0~
In preparing the mixtures o~ the present invention;
it i~ sometimes deslrable to have the polyepoxlde ln a mobile llquld condition when the poly~IA) compound or polymer 1B added so as to facllltate thorough mixing. m e polyepoxldes as de~cribed below are generally vlscous to solld material~ at ordinary temperature~ Wlth those that are liquid, but too viscous ~or readily mlxlng, they are either heated to reduce the vlscosity or have a liquid solYent added thereto ln order to provide rluidity. Normally, ~olld members are likewlse either melted or mlxed with a llquid solventO Varlous solvents are sultable for achlevlng fluidlty o~ the polyepoxides.
These may be volatlle solvents ~hich escape from the mixed composltions by evaporation be~ore or during the curlng cuch as ketones llke acetone, methyl ethyl Xetone, methyl n-propyl ketone, methyl lsobutyl ketone, lsophorone, etc., esters such as ethyl ~cetate, butyl acetate. CellosolYe~
acetate (ethylene glycol monoethyl ether acetate), n~thyl Cellosolve acetate (acetate of ethylene glycol monomethylether~, etc.
ether alcohols such as methyl, ethyl or butyl ether of ethylene glycol or dlethylene glycol; chlorinated hydrocarbons su~h as trichloropropane, chloroform, etc.
To sa~e expense~ these active solvents may be u~ed ln admixture wlth aromatlc hydrocarbons such as benzene9 toluene, xylene, etc., and/or alcohols such as ethyl, lsopropyl or n-butyl alcohol. Solvent~ whlch remaln in the cured composltions may also be used, ~uch as dlethylphthalate, or llquld monoepoxy compounds includlng glycldyl allyl ether, glycldylphenyl ether~ atyrene oxldeg and the llke, as well as cyano-substltuted hydrocarbons, ~uch as acetonltrile. It i8 also convenient to employ a glycidyl polyether Or the dihydrlc phenol in admlxture wlth a normally liquld glycidyl polyether o~ a polyhydrlc.
alcohol.
The polyepoxldes to be used ln the proce3s of the lnventlon include those organlc compounds contalnlng a plurallty of epoxy groups, l.e~ groups of the ~ormula C-C
~hese compounds may be saturated or unsaturated, allphatic, cycloallphat`lc, aromatic or heterocyclic and may be substituted 1~ deslred wlth 3ubstltuents, such as #~rademark ~. . ..... .

~6 chlorlne atoms~ hydroxyl groups, ether radical~J and the llke. m ey may also be monomerlc or polymerlc~
For clarlty, many o~ the polyepoxides and particularly those of the polymeric type have been de~ined ln terms of epoxy equivalent value. The meaning of this expression is described in the U.S. 2,6333458.
If the polyepoxide materlal conslstq of a single compound and all o~ the epoxy groups are lntact~ the epoxy equivalency wlll be integeri3, such as 2, 39 4 and the like, However, in the case of the polymerlc type polyepoxldes many of the materials may contaln some of the monomeric monoepoxideis and/or contaln macromolecules of somewhat dif~erent molecular weight so the epoxy equivalent value may be qulte low and contain rractional values. The polymeric material may9 for example, have epoxy equivalent values, such as 105, 1. B, 2 . 5, and the llke.
Various examples of polyepo~ides that may be used in the process of the invention are glven ln U.S. 2j633,458 and it ls to be understood that i~o much o~ the disclosure o~ that patent relatlve to examples of polyepoxldes ls incorporated by re~erence into thls specification.
A group -of polyepoxide~ which are not speclflcally illustr~ted in the above~patent but are o~ particular value are those which contain terrninal epoxy groups of the formula i (II3 and lnclude glycldyl polyethers of polyhydric phenols or polyhydrlc alcohols. These preferred resln-~orming polyepoxides may be termed "ethoxyllne" reslns and are more particularly deflned aæ orga~ic compounds ~ree of functional group~ other than hydroxyl and epoxy groups whlch contain at least 2 vic-epoxy groups in which the oxygen ls attached to ad~acent singly-bonded carbon atoms and which have a molecular weight ln the range Or about 250 to 5,000. The polyepoxldes havlng epoxy equivalencies from lO0 to 1~025 have generally been ~ound useful. Those having greater epoxy equivalencles up to about 1500 or hl6her may be used when special care is taken to select the comonomer(s) o~ the formula IA copolymer as well as the proportion(s) thereof relative to polyepoxide, to provide mutual compatibility.
Polyepoxides that may be used lnclude the "ethoxylene resins" available under the trademarks of D.E.R.*, D.H.R.~, Epon~9 Eponex~, or Aral~ite~ resina. They lnclude polyether derlvatlves o~ polyhydric phenol containing epoxy groups and may be prep~red by effectlng reaction between epichlorohydrin and a polyhydroxy phenol or alcohol, such as Bis-Phenol A, or the completely hydrogenated product of Bls-Phenol A.
There may also be used as the polyepoxide component additlon copolymers of glycidyl acrylate, glycidyl methacrylate, glycidyl vlnyl ether, or glycldyl vlnyl sul~ide with other monoethylenlcally unsaturated comonomers contalning a group of the fo~mula H2C=C such as Cl-C18 alkyl ester of acryllc acld or methacryllc acld, ~tyrene, vlnyl acetate~ acrylonltrile, and vinyl~
chlorlde. The copolymers may contaln up to 40% by welght of one or more Or the glycidyl esters or ethers~ and prererably contaln about 10% to 30% by welght thereof, The vinyl copolymerizatlon system ~ust mentioned may be used to incorporate both components in a slngle polymerlc compound. By lncluding ln the comonomers a 2,2 dlalkyl-oxazolldlnylalkyl (meth)acrylate or a 2~2-alkylene analogue, a copolymer o~ an unsaturated glycidyl-contalning monomer wlth the ~ormula IA-containlng unsaturated oxazolidlnyl monomers deflned hereinabove may be produced under anhydrous condltlons so *~rademark ~, . -- 10 ~

that ~ipon spreading the copolymer as a coatlng Or adhesive and sub~ectlng the latter to molsture~ the pendant oxazolidinyl cycllc groups hydrolyze to form secondary amlne groups ln the copolymer chain whlch cure the vic-epoxy groups therein. The copolymers contaln about one equlvalent of latent amlne ~or each equivalent o~ epoxy thereln.
In the following examples which are lllustratlve o~
coating and adhesive embodlments Or the present invention, the parts and percentages are by weight and the temperatures are ln Celsius degrees unless otherwlse noted.
Example I~ Preparation of a MEOXEMA Copolymer and a Crosslinked Coatin~ with it and a resin-formln~ Pol~e~xide A) 2-Eth~1~3 (?-hydroxyethyl)-?-Methyl-Oxazolldine ~MEHEOX) A mixture of 315 g (3 mols~ of diethanolamine, 432 g (6 mols) of methylethylketone, and 100 ml of cyclohexane ls stirred and heated to reflux using a Dean-Stark tra? to separate the water formed. The mlxture is stirred and re~luxed for a total o~ 31-1/2 hours during which 54 ml ~f aqueous layer, 85g water and 15% rnethyl ethyl ketone by NMR, is collected (85% of the theoretlcal amount o~ water of reactlon). The mixture is then concentrat.d and the residue dlatilled to glve 373 g (78%
yield) of product (MEHEOX), b,p. 85-88C/2.5-3.0 mm Hg~
~) M acr~late of_MEHEOX (MEOXEMA~
A mixture of 2800 g (28 mols) o~ methyl methacrylate, 1114 g (7 mols~ of 2-ethyl-3-(2-hydroxyethyl~-2-methyl-oxazolidlne (MEHEOX), 20 g of hydroquinone and 17.5 g (0.07 mol) of dibutyltin oxlde is stirred and heated while a ~low stream o~ dry alr ls passed thru the mixture. The vapor is ~r ctionated u~l~g a 10-stage Older~haw column equipped with an l~othermal dlstillation controller set ~or 50%
takeo~ below 65C. Qnd 100~ reflux when the temperature exceeds 65C. After three hours, 83% o~ the theoretical amount of methanol has been collected and a preclpltate beglns to form ln the reactlon mixture. The mixture i8 cooled to room temperature and riltered. The solid i8 washed with methyl methacrylate and air-dried to glve 8.5 g o~ a tan powder whlch contains 42% tin by elemental analysis Excess methyl methacrylate ls strlpped from the filtrate and 1326 g of a mlxture o~ product and 2-ethyl-3-2(2-hydroxyethyl)-3-methyl-oxazolidine is distllled from the flaskO Thls crude product ls lnhlblted with 10 g of hydroquinone and redistllled thru an eight-inch Vlgreaux column, agaln uslng an alr ~parge, to give 1007 g (63%
yleld) of product, b.p~ 107-109~C,/1.8-2.0 mm Hg.
C) Copolymer of St~rene and MEOXEMA (57~8~/42,11 To 250 g of xylene, maintalned at reflux (138C.) ls added contlnuously (dropwlse~ over a perlod of

4 hours a solution of 289.43 g of styrene, 210.57 g of MEOXEMA and 6.67 g of a 75% solution of t-butyl peracetate in mineral spirit~ (available commerclally under the trademark deslgnation Lupersol~ 70). The polymerl~ing solution and the ~eed solut~on Or monomers and catalyst may both be sparged continuously with dry nltrogen during the 4-hour perlod of addition.
When the addltion i8 completed~ heating is continued ror 0.5 hour. Then an additlonal charge of 0.67 g of Luper~ol 70 i3 added and heating at reflux ~s continued for 1 hour berore coollng the completed resin to amblent temperature 9 D) oatin~ with a Polyepoxide To 10.0 g of the cop~lymer prepared in Part C

5~ added 5.00 g of ethoxyethanol acetate and 4~40 g of a ,i,~

50% solutlon of Epon~ 828* dissolved ln ethoxyethanol acetate. After mlxing~ a 5 mil wet rilm ls coated on a phosphatlzed steel panel (Bonderlte~ 1000). After 2 weeks curing at 70F/50% RH~ the KHN ls 17.6 and reverse lmpact greater than 10 in~lbs. Heatlng at 140F for 24 hrs.
lncreases the KHN to 19.6 and the reverse lmpact to more than 150 ln-lbs. Chemical reslstance of the coating ls excellent both before and after heating.
A llquid dlglycidyl ether Bis-phenol A resln having a visco lty of lOgO00~16~000 cps. (25C) and an epoxide equivalent welght of 185-192.

Example IIo Preparation of a 2,~-Dialkyloxazolidlnyl Functlonal Polyurethane and Coatin~_~ith Polyepoxy Resins A) A solutlon of 44.2 g (0.1 mole N=C=0) Or an isocyanate terminated polyurethane prepolymer (avallable commerclally under the trademark designation Spenkel~
P-49-60CX) and 15.9 g (0.1 mole) of 2-ethyl-3-(2,hydroxy-ethyl)-2-methyl-oxazolldlne 13 prepared ln a tlghtly stoppered bottle and held at ambient temperature for 24 hoursO The viscous product ls dlssolved in 60.0 g of anhydrous butyl Carbitol~. Thls solutlon (II-A) contains 0.76 MEq/g of amlne by titration in glacial acetlc acid with perchlorlc acid using crystal violet indlcator.
B) To 15.0 g (11.4 MEq) of Solution II-A there ls added 2.0 g (11,4 MEq) of Epon* 828 and after thorough mlxing, a coating ls prepared on a Bonderlte* 1000 test panel at a 5-mil wet film thickness. After curing under amblent conditions (7 days/25C, 1 day/60C) the film ls swelled but not dissolved by methylene chlorlde (MDC) and ls not affected by two hours exposure to cheese cloth patches wet wlth 10% aqueous acetlc acld and toluene.
Coatlng solutlon ln a stoppered bottle ls fluid after nearly 3 months storage at amblent temperature~

*~rademark ~"~

~ L8 Example III~ Pre~aratlon of the tri-2[3(2-ethyl-2-methyl-oxaolidlny~ )I-ethyl carbamate of 1~6-hexane diisocyanate trimer A) Oxazolidine Component A ~olution of 19.9 g (0.125 mole) Or 2-ethyl-3-(2-hy~roxyethyl)-2-methyl-oxazolldlne, 26.6 g (0.125 equivalents N=C=O) of a 75% solutlon of 1,6-hexamethylene-diisocyanate trlmer (available under the trademark Desmodur~ N) in ~ellosolve~ acetate, and 42.2 g of toluene ls heated at 95~C ~or 11 hours. AIter cooling to room ~emperature9 the 80111tiOIl (III-A) 18 Pilkered and found to contaln 1.44 MEq/g of amlne by titrationO
B) Co ting w~ ~h Polyepo~lde To 10~0 g (1.44 MEq) of the polymer Solutlon 15 III-A is added 2 45 g of Epon* 828, and after mixing, a coating (5 mils wet) ls prepared on a Bonderite* 1000 panel. After curing 7 days/25C, 1 day/60C a tack free, clear, tough fllm is obtalned that ls unaffected by exposure at ambient temperature, to pa'cches of cheesecloth 20 saturated with 10% acetlc acid and toluene, for 2 hours.

Example IV. Dlalkyloxazolldinyl Diester and a Coatln~
Prepared ~ro lt and a ~olyepoxl~e A) Dlester In a 500-ml three-necked flask, fitted wlth a 25 stirrer, nitrogen sparging tube and a mirrored, vacuum ~acketed, sieve plate fractionation column wlth reflux conden~,er and a proportionally tlmed distillatlon take-off mechanism, a solutlon of 125 g o~ tolune, 79.6 g (0.5 mole) of 2 ethyl-3-(2-hydroxyethyl)-2-methyl-oxazolidlne, 43.8 g (0.25 mole~ of dlmethyl adlpate, and 0.27 g (OD005 mole) of sodlum methoxlde is heated at reflux for 6 hours. During thls tlme methanol/toluene 3~rademark azeotrope boiling at 65C is collected yieldlng a total distillate weighing 26.2 g correspondlng to l5.8 g o~
methanol (99% of theory). Two successive addltional charges o~ 0.30 g of sodlum methoxide are added to the re~luxing solution during thls 6 hour period.
Upon coollng to room temperature the solution is filtered to remove insoluble catalyst residues. The clear flltrate (IVA) contains 4.3 MEq/g amlne.
B) Coating To 10.0 g (4300 MEq) o~ the solutlon prepared ln Part IV-l ls added 7.3 g (43.0 MEq~ o~ Epon~ 828. Arter mixing 9 a 5 mll wet ~llm coating 1~ prep~red on Bonderlte~
1000. A~ter curing for 7 days/25C, l day/60C a tack free, clear~ tough coatlng ls obtained which ls swelled but not dissolved by methylene chlorlde and whlch is unaffected by exposure for 2 hours to cheesecloth patches saturated with 10% aqueous acetic acld and toluene.

Example V. Polymer Contalnlng Both Epoxy and Dialkyloxazoildinyl Functlonallty and a Coatin~ From It.
A) Polymer To 300 g of refluxlng xylene, sparged wlth dry nltrogen gas, there ls added over a period Or 4 hours, a solutlon Or 90.114 g of methyl methacrylate (MMA), 129.06 g 2~ Or butyl methacrylate (BMA), 48.23 g of 2-(2,2-dimethyl-oxa~olidlnyl) ethyl methacrylate (DMOXEMA)g 32.27 g of glycldyl methacrylate (GMA), and 8.00 g o~ Lupersolf 70~
When the addltion is complete the solution ls maintained at reflux for 0.5 hoursg then, 0.80 g Or Lupersol* 70 is added and refluxlng ls continued ~or 1 0 hourg be~ore cooling to room temperature. The solution (V-A) ls straw yellow and clear~ The monomer components of this polymer are ln the molar ratio of ~rademark 4/4/1/1//MMA/BMA/GMA/DMOXEMA.
The solution (V-A) of poligomer appears unchanged after 4.5 months storage ln a stoppered bottle at ambient temperature.
B) Coatin~
A clear coating of (~-A) ls cast as a 6-mil wet ~ilm on Bonderite* 1000. The coating is tack-free after 15 min. at ambient temperature. A~ter curlng 18 days at ambient temperature the coatlng is swelled by methylene chlorlde; it show ~light bllstering and haze when expo3ed for 1 hour to a cheesecloth patch saturated wlth 10%
aqueous ~cetlc acld; it 18 not attacked by 10~ ~o~ium hydroxide solution, and i8 only sllghtly ~wollen by gasoline and methanol after 1 hour.

Example VI.
A) Part A) of Example I is a process for maklng MEHEOX, l.e., 2-ethyl-3-(2-hydroxyethyl)-2-methyl-oxazolldine by reaction of diethanolamlne with methyl ethyl ketone. Replacement of the latter ketone with acetone ln molarly correspondlng amount ylelds 3-(2-hydroxyethyl)-2,2-dimethyl-oxazolidine, hereln referred to by the acronym DMHEOX9 l.e., dimethyl-hydroxyethyl-oxazolldlne. Replacement of the ketone wlth cyclo-pentanone or cyclohexanone yields 3-(2-hydroxyethyl)-2,2-tetramethylene- or 3-(2-hydroxyethyl)-2l2-pentamethylene-oxazolldlne.
For comparlson purposes, lsobutyraldehyde is used ln place o~ the ketone so that the reaction with diethanol amine produces 3-(2-hydroxyethyl3-2-isop~opyl oxazolidlne (IPHEOX) in whlch only one of the hydrogens on the 2-carbon positlon of the oxazolldinyl ring ls replaced with an alkyl group~ Likewlse, 3-(2-hydroxyethyl)-oxazolldine (HEOX) is obtalned when formaldehyde is used lnstead of lsobutylaldehyde.

*~rademark B~ The procedure of P~rt B) of Example I i8 used to prepare the acrylate (using methyl acrylate lnstead of methyl methacrylate) or the methacrylate o~ the varlous 3-(2-hydroxyethyl)-oxazolldlnes mentioned ln Part A) hereof. The methacrylate of HEOX 18 referred to simply by the acronym, OXEMA; the methacrylate of IPHEOX is rererred to a3 IPOXEMA; that of MEHEOX9 MEOXEMA; that of DMHEOX~
DMOXEMA, and 80 on.
C) Copolymers are prepared ~rom the various methacrylates produced in Part B) hereof by the general procedure descrlbed ln Example IC~ herelnabove wlth styrene (S)9 acrylonitrlle (A)~ methyl methacrylate (MMA), butyl methacrylate (BMA).
Table I, in the first column gives the ldentification number (Id. No ) Or nlne copolymers conformlng to the requlrements of the lnve~tion that both hydrogens of the 2-carbon in the oxazolldine ring are substituted by alkyl groups or an alkylene group and three comparlson copolymers, two of them belng ldentlfied by Cl and C2 ln which the 2-posltlon of the oxazolidine ring has 2H atoms (SO) and one H (SI) respectlvely but otherwlse i~ slmilar to copolymer Id. No. 5 Just above those two controls. The third comparison copolymer ls C3 to be compared wlth Id.
No. 90 The second column gives the compositlon of the copolymers and the molar ratios of the components thereo~. The numeral ln (~ in thls column indicates the percentage of t butylperacetate initlator used, based on total monomer weightO The next column llsts the grams of comonomer used ~nd the partlcular comonomer by a letter symbol~ The next column ls the grams o~ oxazolidlne morlomer and the partlcular one used by symbol (see the key in the footnote)~ The next column lndicates the grams o~
solvent used; the next to last column glves the % sollds in the product 9 and the last column glves the amine titer in mllliequlvalents per gram (ME/g) of the productO

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~ ~ ~ 6 D) Coatlng compositions are prepared by mlxlng a 10-gram portlon of each Or the products listed in Table I
identlfled therein with Id. Nos. 1 through 5~ C1J C2, and Id. Nos~ 6 through 9 with an amount of 100% polyepoxide condensate, namely the commercial product Epon~ 828 such that the ratio of NH~epoxy equivalents i8 1: 1 . Also, 10 g of the solutlon II-A (prepared ln part A) oT Example II of polyfunctivnal resin-forming condensate (of 2-ethyl-3-(2-hydroxyethyl)-2-methyl-oxazolldine with the l~ocyanate-termlnated polyurethane prepolymer) 18 mlxed wlth the ~amepolyepoxide to provlde a 1:1 equivalency ratlo ~f NH:epoxy~
Table II ln column 1 liæts the oxazolidlne copolymer or resln by the Id. Nos. ln Table I and by II-A
lS ~or the last-mentioned product. The second column Or Table II gives the amount of Epon~ 828 added. The third column refers to the properties o~ 5-mil wet ~llm cast on Bonderite~ 1000 kest panels a~ter 20 hours and the fourth column gives the methylene dlchloride (MDC) reslstance of such fllms at 1 to 4 days. The next seven columns give the appearance, hardness (Knoop Hardness No. - KHN), and various reslstances after 3 weeks ambient curing (70F/50%
relative humidlty) of such ~ilms. The ~inal column glves the stabillty of the coatlng solutlon when stored ln the absence of molsture ln closed cans or drums at 25C.

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E) Coating compositlons are prepared by ~lxing 10-gram portions of the product~ llsted ln Table I
identlfied wlth Id. No. 1 through 5, Cl, C2, 6 through 9 and C3, with an amount of a 75% solutlon in xylene of Epon~ 1001 that provldes an NH~epoxy equlvalent ratlo of 1:1 or 1:2 as lndicated ln the second column of Table III. Also, a 10-gram portlon of solution IIA and of solution IIIA are mixed with enough of the polyepoxlde to provide an NH/epoxy equlvalent ratlo of 1:1 and also an additional 10-g portion of III-A ls mixed wlth enough o~
the polyepoxide to provide an NH/epoxy equivalent ratio of 1:20 Table III glves the properties of the test fllm prepared from the mixtures as in D) above and the stabillty o~ the coating mixture. The same Tootnotes apply as in Table II.
The polyepoxide used in Part E) and ln Part B) are oT the class generally defined as the glycidyl polyethers of Bis-phenol A obtained by reactlng 2,2 bis-(4-hydroxy-phenyl)propane with epichlorohydrin as described in U.S.
patent 2,633,458.

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F) Coating composltlons are prepared wlth 10-gram portlons of oxazolidine copolymer Id. Nos. 1 through 9 of Table I by mlxlng each portlon with a diglycidyl ether condensate of Bls-phenol A which has been hydrogenated to saturate the aromatic groups. The polyepoxide used thereln may therefore by properly deslgnated a glycidyl polyether of 232-bls-(4-hydroxycyclohexyl)propane. This saturated polyepoxide is preferred for reasons of durability agalnst ultravlolet light. An amount of the 3aturated polyepoxide thereby obtained i~ added to each of the 9 copolymers to provlde sn equlv~leney ratio o~ 1:1 o~
NH/epoxy ln the mixture. A 50% ~olutlon, ln xylene or Propasol~ B, o~ a polyepoxide of the type available under the trademark Epone~0 151.1 is used. A comparison mlxture of a 10-gram portion Or a commerclally avatlable condensatlon product Or a long-chaln ~att~ acid and an allphatic polyamine, identlfied as V ln Table IV, that has been used as a polyepoxy resin curlng agent is provlded.
The mixtures are coated, stored, and tested ln the same way as the mixtures and films thereof were tested in D) and E) herelnabove~ Also, the same footnotes as ln Table II apply to the tabulation of results ln Table IV
~ollowlng.
The present lnvention ls the result of the dis-covery that (poly)functlonal oxaæolldines in whlch both hydrogen atom of the II-position carbon in the ring ls substltuted by alkyl groups or an alkylene group serve as latent polyepoxlde curlng agents and resin formlng poly-epoxides can be mlxed wlth the latent curlng agent and stored in the absence of moisture for months without notlceable change or reactlon but that on ~ormation of films of the compositlon and exposure thereof to moisture, even ambient air havlng a relatlve humldlty Or at least 20%~ and preferably at least 50~, provides reasonably rapld ~Trademark V~,4 ~8~

curlng to form h~rd, hlgh performance coatings. In contrast9 mlxtures of a resin-forming polyepoxide with - (poly3functional oxazolidines ln which nelther or only one o~ the hydrogen atoms on the 2-posltion carbon is replaced with alkyl or alkylene groups lack stabllity on storage; even in the absence o.~ molsture such an oxazolidine undergoes reactlon dlrectly wlth the polyepoxide as a tertlary amlne that causes gelatlonO
Apparently the 2,2-dialkyl or 2,2-alkylene oxazolinyl rings of Formula IA are in effect sterically hlndered and must be hydrolyzed by moisture to produce an hydroxyalkyl group of formula IB supra to cure the polyepoxide~

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.~, EXAMPLE VII Water-Reduced Coatings .

A) To 689 g Or a solutlon containlng 66.6~ polymer sollds of a copolymer of styrene and MEOXEMA (3:1 molar ratio) ln xylene, having an amine titer of 1.20 ME~g of solution, is added 165.4 g o~ Epon~ 828 resln. The resultlng solution is heated to 100C and xylene is removed by dlstillatlon under reduced pressure until the reslnous distillation residue contalns about 93-4% polymer sollds. The resinous dl~tlllation re~idue is then diluted ~lth 111.8 g of methyl n-propyl keton~ to obtaln ~ mlxture containlng 80% polymer solids.
To 50 g of this dlluted mlxture there 13 added 1 g Or phenoxyethanol and 1 g of Capcure~ 65 emulslfier followed by the further addltlon o~ 16.7 g of water, dropwise and while stirring rapldly, thereby obtalning a water-reduced coating emulslon.
Thls emulsion is then cast as a 5 mll wet film coatlng on Bonderite~ 1003 lmmediately after preparatlon and again after the emulsion has been allowed to stand 5 hours at ambient conditlons. Both of the resultlng coatlngs are white when freshly cast but become clear after standlng 30 mlnutes at amblent conditionsO After curlng 7 days at ambient condltions~ the coatlngs are swelled, but not dissolved, by methylene chlorlde, which property lndicates that crosslinklng has occurred.
B) To 189 g o~ a solutlon o~ a copolymer of lsobutyl methacrylate and MEOXEMA (3:1 molar ratio) in xylene, having an amine titer of 1.16 ME/g Or solutiong is added 5105 g of Eponex~ 151.1 resin (an allphatic epoxlde resin). The resultlng solution is heated to about 100C
and xylene ls removed by distillatlon under reduced pressure. The reslnous distillatlon residue ls then dissolved in 28.2 g of methyl n-propyl ketone. To 50 g of thls solutlon there is added 2.0 g of phenoxyethanol and 1.5 g of Capcure~ 65 emulslfier ~,~Trademark 26 ~

followed by the ~urther addition 31.0 g of water;
dropwlse and whlle stlrring rapidly, thereby obtainlng a water-reduced coating emulslon.
Thls emulsion is then cast as a 7 mil wet fllm coatlng on Bonderlite~ 1000 panels. After drying for 30 mlnutes at amblent temperature, the coating ls clear (transparent). After curing for both 30 minutes and for 24 hours at ambient temperature the coatlng is swelled, property lndlcates that crosslinklng has occurred~
Preliminary outdoor durabllity data lndlcates that the coating of part B) of thls example possesses more prolonged outdoor durabillty than do similar coatings derived from photochemically reactlve aromatic components such as styrene and bis-phenol A.

EXAMPLE VIII. Preparation of Adheslve Composltion A) Amlne Copolymer To 150,0 g of xylene, heated at 105C wlth stirring and maintained under a nltrogen atmosphere, is added dropwise over a period o~ 4 hours a solution of 323.0 g of isodecyl methacrylate, 27.05 g of MEXOEMA and 10.50 g of t-butyl peroctoake. When the addition is complete, an addltlonal charge of 1.05 g of t-butyl peroctoate i6 added to the stirred polymerizatlon reaction mlxture and the temperature is malntalned at 105C for 30 mlnutes before cooling the product.
The product i9 a clear, light yellow solution, contains an amlne titer of 0.21 ME/g and has a ~w of 27,9000 and a ~n of 7360 (determined by gel permeation chromatography).
B) Adhesive Composltion To lO.O g of the ~olutlon obtained in part A3 above i5 added 0O42 g of Epon~ 828. The resultlng solution is coated as a 2 mil wet fllm on Bonderite~ 1000 ~0, ~ 27 - ~$6~

panels. After~drylng overnlght at amblent temperature, a very tacky and adheslve coatln~ i6 obtalned. The coated film ls suitable for use as a pressure sensitlve adhesive and adheres to nylon, propylene and polyethylene terephthalate ~ilms. The coating ls then ~tored in a ~toppered vial at room temperature. After 30 days of storage, the appearance of the solutlon is unchanged from its initial appearance.

.~!'~'~ i ~.

Claims (12)

We claim:

1. A hydrocurable composition adapted to be used for coating, impregnating, or adhesive purposes at ambient conditions of temperature and relative humidity comprising an anhydrous mixture of (1) a resin-forming polyepoxide containing at least two vic-epoxy groups and (2) a polyfunctional compound containing at least two cyclic oxazolidinyl groups of the formula (IA) wherein m is 2 or 3, and R1 and R2 are either separate alkyl groups, each having at least one carbon atom, or are joined directly together to form an alkylene group of 4 or 5 carbon atoms, the compound (2) containing no other amine nitrogen groups, and the amount of (2) being sufficient to provide at least about one equivalent of epoxy group for each equivalent of amine in (1), the composition, in the absence of moisture being stable for months.

2. A composition according to claim 1 wherein the polyfunctional compound (2) is a condensation product of (a) a compound having the cyclic group of the formula IA
as defined therein with a hydroxyalkyl group attached to the N atom thereof with (b) a polycarboxylic acid or a polyisocyanate, or (2) is a transesterification product of (a) with a polyester of a polycarboxylic acid.

3. A composition according to claim 1 wherein the polyfunctional compound (2) is a vinyl addition copolymer Or monoethylenically unsaturated monomers having a group comprising at least one monomer selected from the acrylic acid or methacrylic acid esters of a hydroxy(C2-C3) alkyl group substituted on the N atom of the cyclic group of formula IA as defined therein.

4. A composition according to claim 3 wherein the copolymer also comprises at least one monomer selected from styrene, vinyltoluene, acrylonitrile, and C1-C18 alkyl esters of acrylic or methacrylic acid.

5. A composition according to claim 1 wherein m is 2.

6. A composition according to claim 3 wherein the compound (2) is a copolymer of 2,2-dimethyl-3-(meth)-acryloxyethyloxazolidine and at least one monomer selected from styrene, vinyltoluene, acrylonitrile, and C1-C18 alkyl esters of acrylic or methacrylic acid.

7. A composition according to claim 3 wherein the compound (2) is a copolymer of 2-ethyl-3-(meth)acryl-oxyethyl-2-methyl-oxazolidine and at least one monomer selected from styrene, vinyltoluene, acrylonitrile, and C1-C18 alkyl esters of acrylic or methyacrylic acid.

8. A composition according to claim 3 wherein the compound (2) is a copolymer of 2-n-propyl-3-(meth)-acryloxyethyl-2-methyl-oxazolidine and at least one monomer selected from styrene, vinyltoluene, acrylonitrile, and C1-C18 alkyl esters of acrylic or methacrylic acid.

9. A composition according to claim 1 wherein the polyepoxide (1) is a glycidyl polyether of 2,2-bis(4-hydroxyphenyl) propane.

10. A composition according to claim 1 wherein the polyepoxide (1) is a glycidyl polyether of 2,2-bis(4-hydroxycyclohexyl) propane.

11. A method for making and using a hydrocurable polyepoxide composition containing a latent curing agent which comprises mixing, in the absence of moisture, (1) an essentially anhydrous resin-forming polyepoxide containing at least two vic-epoxy groups and (2) a polyfunctional compound, as a latent curing agent for the polyepoxide, containing at least two cyclic oxazolidinyl groups as defined in claim 1 in the relative proportions stated therein, storing the composition in tightly closed containers that serve to exclude water in liquid or vapour form, as in humid or moist ambient air until the time of use or transport to the place of use, and subsequently applying the composition by spreading a film of it over or on a surface to be coated, impregnated, or adhesively joined to another surface, exposing the film, during or after its formation, to ambient moist air at ambient temperature and having a relative humidity of at least 20% to effect curing of the polyepoxide by reaction with the secondary amine formed by hydrolytic splitting of the oxazolidinyl ring in the latent curing agent (2).

12. The method of claim 11 wherein the latent curing agent for the polyepoxide is mixed with any additional anhydrous ingredients that are inert to (1) and (2).